1. Field of the Invention
The present invention relates to an image forming apparatus and a control method therefor, which feature control of input and output of data to a nonvolatile memory mounted in a process cartridge removable from the image forming apparatus.
2. Related Background Art
Modern image forming apparatuses such as laser printers, copiers and facsimiles can perform data transmission to a nonvolatile memory mounted in a process cartridge removable from the image forming apparatuses.
FIG. 5 is a flowchart illustrating a conventional method of transmitting data to a nonvolatile memory. In FIG. 5, it is detected in step 501 whether such condition that data transmission to a nonvolatile memory is needed takes place or not. If data transmission is needed, data transmission to the nonvolatile memory is started in step 502. Then, it is confirmed in step 503 whether the data transmission is finished. After that, the control procedure returns to step 501 from which the sequence of control operations is repeated.
However, the above-mentioned conventional method has the following drawbacks. In other words, data transmission to the nonvolatile memory becomes unstable when a door open and closed for attaching or detaching a process cartridge is opened during the data transmission to the nonvolatile memory mounted in the process cartridge. This runs the danger of losing part of data to be stored in the nonvolatile memory. Further, in the event that part of data is lost, there is no means for recognizing the data loss, which impairs the reliability of data stored in the nonvolatile memory.
The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to provide an image forming apparatus and a control method therefor, capable of avoiding possibilities of any data loss even if, for example, a door is opened during data transmission to a nonvolatile memory mounted in a process cartridge. The image forming apparatus and its control method also enable restart of data transmission to a proper nonvolatile memory alone after closing the open door.
An image forming apparatus according to the present invention comprises: an attachment device as a functional member in image forming, removably attached at a predetermined position; an open-close member for opening and closing when the attachment device is attached or detached; a memory means mounted in the attachment device for storing data; a detection means for detecting opening and closing of the open-close member; and a control means for halting input and output operations of data to the memory means when opening of the open-close member is detected on the basis of the detection results of the detection means.
In the image forming apparatus and according to another aspect of the present invention, wherein the memory means has unique identification information, the control means stores the identification information read out of the memory means, the control means halts the data transmission to the memory means when opening of the open-close member is detected during data transmission to the memory means on the basis of the detection results of the detection means, while the control means includes a temporary memory means for storing the data concerned, the control means reads the identification information out of the memory means to compare the read-out identification information with the identification information stored in the temporary memory means before the open-close member is open when the open-close member is closed again, and the control means re-executes the data transmission to the memory means if both pieces of identification information correspond to each other.
In the image forming apparatus and according to still another aspect of the present invention, the memory means has unique identification information, the control means stores the identification information read out of the memory means, the control means halts the data transmission to the memory means when opening of the open-close member is detected during data transmission to the memory means on the basis of the detection results of the detection means, while the control means includes a temporary memory means for storing the data concerned, the control means reads the identification information out of the memory means to compare the read-out identification information with the identification information stored in the temporary memory means before the open-close member is open when the open-close member is closed again, and the control means deletes the data stored in the temporary memory means and writes the read-out identification information over the identification information stored in the temporary memory means if both pieces of identification information do not correspond to each other.
In the image forming apparatus and according to yet another aspect of the present invention, the memory means has unique identification information, the control means stores the identification information read out of the memory means, and the control means halts the data transmission to the memory means when opening of the open-close member is detected during data transmission to the memory means on the basis of the detection results of the detection means, while the control means includes a temporary memory means for storing the data concerned, the control means reads the identification information out of the memory means to compare the read-out identification information with the identification information stored in the temporary memory means before the open-close member is open when the open-close member is closed again, and the control means deletes the data stored in the temporary memory means and generates a signal indicative of failure of the data transmission if both pieces of identification information do not correspond to each other.
Another image forming apparatus according to the present invention is capable of removably mounting therein a replacement unit having a memory means, the apparatus comprising: an open-close member for opening and closing when the replacement unit is attached or detached; a detection means for detecting opening and closing of the open-close member; and a control means for controlling input and output operations of data to the memory means, wherein the control means includes a temporary memory means such that when the control means confirms a signal sent from the detection means during data transmission to the memory means, detects such a state that the open-close member is open, and stores the data concerned in the temporary memory means.
A control method for an image forming apparatus according to the present invention, in which the image forming apparatus includes an attachment device as a functional member in image forming, removably attached at a predetermined position, an open-close member for opening and closing when the attachment device is attached or detached, and a memory means for storing data, mounted in the attachment device, comprises the steps of: detecting opening and closing of the open-close member; and halting input and output operations of data to the memory means when opening of the open-close member is detected in the detection step.
In the control method and according to another aspect of the present invention, the memory means has a storage area for storing unique identification information, and the control method comprises the steps of: detecting opening and closing of the open-close member during input and output operations of data to the memory means; halting the data transmission and storing in a temporary memory means the data currently transmitted when opening of the open-close member is detected in the detection step; reading the identification information out of the memory means when then closing of the open-close member is detected in the detection step; and comparing the read-out identification information with the identification information stored in the temporary memory means before the open-close member is open, and re-executing the data transmission to the memory means if both pieces of identification information correspond to each other.
In the control method and according to still another aspect of the present invention, the memory means has a storage area for storing unique identification information, and the control method comprises the steps of: detecting opening and closing of the open-close member during data transmission to the memory means; halting the data transmission and storing in a temporary memory means the data currently transmitted when opening of the open-close member is detected in the detection step; reading the identification information out of the memory means when then closing of the open-close member is detected in the detection step; and comparing the read-out identification information with the identification information stored in the temporary memory means before the open-close member is open, and deleting the data stored in the temporary memory means and writing the read-out identification information over the identification information stored in the temporary memory means if both pieces of identification information do not correspond to each other.
In the control method and according to yet another aspect of the present invention, the memory means has a storage area for storing unique identification information, and the control method comprises the steps of: detecting opening and closing of the open-close member during data transmission to the memory means; halting the data transmission and storing in a temporary memory means the data currently in input and output operations when opening of the open-close member is detected in the detection step; reading the identification information out of the memory means when then closing of the open-close member is detected in the detection step; and comparing the read-out identification information with the identification information stored in the temporary memory means before the open-close member is open, and deleting the data stored in the temporary memory means and notifying the user of the image forming apparatus of failure of the data transmission if both pieces of identification information do not correspond to each other.
According to the present invention, opening and closing of the open-close member can be so detected as to properly control input and output operations of data to the memory means mounted in the attachment device. The attachment device is a functional member in image forming, placed in position. This makes it possible to eliminate losses of data to be stored in the memory means, and even if part of data is lost, the user can be informed of the occurrence of the data loss.
These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended drawings as follows.